This invention relates to a lubricant for use in hot forging of aluminum and aluminum alloy components. More specifically, this invention relates to an environmentally acceptable lubricant for use in hot forging aluminum and aluminum alloy components.
Hot forging of aluminum and aluminum alloy components requires the use of a suitable lubricant. Such lubricants are applied to the die of the forge and the workpiece to allow proper movement in the die cavities and to allow the forging process to be repeated many times in succession with or without the re-application of the lubricant. Typically, lubricants of the prior art include one or more organic lead compounds, such as lead naphthenate and lead stearate. The organic lead compounds were found to best facilitate the proper movement of the die during the forging process.
Although organic lead compounds work very well in this application, the use of lead has recently come into disfavor because of the health hazards associated with lead in the atmosphere. During the hot forging of aluminum, some of the organic lead present in the lubricant is dispersed into the atmosphere in unacceptable quantities. Local and national governmental regulatory agencies have banned the use of lead in certain industries, or have severely limited the allowable concentrations of lead in the atmosphere as reflected, for example, in Title 29 of the Code of Federal Regulations. If the use of lead in hot forging applications were to continue, it would be necessary for hot forging facilities to install very expensive exhaust and air filtration systems to lower the concentration of atmospheric lead to acceptable limits. Such exhaust and air filtering systems would not be economically feasible for most aluminum hot forging facilities.
It would therefore be desirable to have available for use in the aluminum hot forging industry an environmentally acceptable lubricant which has the same performance characteristics as lubricants of the prior art, yet without containing lead which could be dispersed into the atmosphere during the hot forging process.